1. Field of the Invention
The present invention relates to new insoluble metallic complexes and to their use as catalysts in various reactions such as hydroformylation, hydrogenation and the preparation of tertiary amines by the reaction of an olefin, carbon monoxide and hydrogen with a secondary amine.
2. Description of the Prior Art
Generally, the catalysts employed in such reactions are soluble catalysts derived from Group VIII noble metals which are difficult to recover because the active catalyst is present in the form of coordination complexes which are dissolved in the reaction medium.
Insoluble catalysts forming heterogeneous catalyst-reaction medium systems and obtained from soluble complexes of noble metals have heretofore been used in various reactions. For example, insoluble ligands prepared from organic polymers with particular functional groups thereon, such as amines, phosphines (French Pat. No. 1,583,037, filed Oct. 1, 1968) and vinylpyridine (U.S. Pat. No. 3,636,159, filed Dec. 19, 1968) have been proposed. Likewise, inorganic compounds into which a phosphor-containing radical has been introduced, either on silica or alumina (British Pat. No. 1,275,733) or an alkoxysilane having a phosphine group thereon or a metallic complex of this alkoxysilane with silica (French patent application Ser. No. 70/45 824, now French Pat. No. 2,071,942, filed Dec. 18, 1970), have been suggested for the hydroformylation of ethylenically unsaturated hydrocarbons to yield aldehydes and alcohols (French patent application Ser. No. 70/45 607, now French Pat. No. 2,073,940, filed Dec. 17, 1970).
The advantage of such catalysts is that the precious, relatively expensive metals therein remain complexed and are not released into the effluent of the reactor and are easily recovered therefrom in their original catalytically active form.
The capacity of these solid catalysts to retain the metal after reaction is due to the coordinating element of the insoluble ligand and not to other coordinating elements ultimately associated with the metal but not directly linked to the insoluble ligand.
Up to the present time, in such catalysts, phosphorus was generally used as a donor heteroatom, and was linked to an inorganic or organic, polymeric matrix. Although these catalysts display satisfactory catalytic activity, the metal retention properties of same have rendered such catalysts economically unsuitable for commercial applications.